Structural and optical properties of dysprosium and europium co-doped with yttrium aluminium garnet nanocrystalline powders prepared by combustion synthesis

This paper presents the study on synthesized yttrium aluminum garnet (YAG), europium-doped YAG (YAG: Eu), and europium and dysprosium co-doped YAG (YAG: Eu, Dy) phosphors prepared by combustion synthesis (CS) using a mixture of fuel (urea). The effects of Eu3+ and Dy3+ ions concentration and annealing temperature were analysed using by X-ray diffraction (XRD) and photoluminescence (PL). YAG nano-crystalline powders were calcined at a temperature range of 900 ℃ to 1200 ℃ for 4 hours. Europium and dysprosium were added in different concentrations in the range of 0.1 at.% to 1.0 at.% to the coarsened pure YAG particles to understand its influences on the optical properties and sintered microstructures. The doping of YAG: Eu and co-doped YAG: Eu, Dy was calcined at 1100 ℃ for 4 hours. X-ray diffraction results showed the phosphors are single-phase YAG with crystalline sizes ranging from 30 to 40 nm. The room temperature photoluminescence results confirmed the introduction of the ion in the host lattice and its optical activation for all the Eu3+ and Dy3+ ions concentrations. The CIE1931 color coordinates showed the sample's emission laid in the near red region for Eu3+ ion concentration and near white region for the addition of Eu3+ and Dy3+ ion concentration. Eu3+ ion concentration of 1.0 at.% achieved the highest emission spectra intensity while the highest emission spectra was achieved at 0.5 at.% for Dy3+ ion concentration and the ion luminescence were preferentially excited with 395 nm for YAG: Eu while, 353 nm for YAG: Eu, Dy wavelength photons